Chemically strengthened glasses are used in many handheld and touch-sensitive devices as display windows and cover plates where resistance to mechanical damage is important to the visual appearance and functionality of the product.
Reduction in the specular reflection from the surface of such displays is often desired, especially for products which are designed for outdoor use. One way to reduce the intensity of the specular reflection, commonly quantified as gloss, is to roughen the glass surface.
One result of such roughening of the glass surface is the creation of “sparkle,” which is a perceived grainy appearance when used in a pixilated display system. Sparkle is manifested by the appearance of bright and dark or colored spots at approximately the pixel-level size scale. The presence of sparkle reduces the viewability of pixilated displays, particularly under high ambient lighting conditions.